1. Field of the Disclosure
The disclosure relates in general to an apparatus and a method for image processing.
2. Description of the Related Art
Current photosensitive elements include, for examples, digital charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) sensors. A saturation level, or full well level, of a photosensitive element usually is designed as one within the operation range of an analog to digital converter. As such, when the analog to digital converter uses a minimal analog gain, the saturation level of a photosensitive element has a clamp point in the operation range. Digital image processing of pixel data usually introduces color distortion or noise of high luminance. In this situation, a higher analog gain can be used such that the saturation level has a clamp point outside the operation range of the analog to digital converter, thereby improving image defects. However, the usage of a higher analog gain decreases the dynamic range of the image, and causes increased noise.